De-ice fairing bond fixture

ABSTRACT

A bond fixture includes a first frame defining a chamber configured to receive a leading edge of a rotor blade and a second frame pivotally coupled to the first frame. The second frame is movable between a first position and a second position. In the second position, the second frame restricts movement of the bond fixture relative to the rotor blade. At least one supporting assembly extends from the first frame towards the chamber. The at least one supporting assembly is adjustable to apply a pressure to an adjacent surface of the rotor blade.

BACKGROUND OF THE INVENTION

Exemplary embodiments of the invention relate to rotary-wing aircraftand, more particularly, to a bond fixture for use during the manufactureor repair of a rotor blade of a rotary-wing aircraft.

Rotary wing aircraft include a plurality of main rotor blades coupled toa central hub. The rotor blades include aerodynamic surfaces that, whenrotated, create lift. The configuration of the main rotor blades,particularly the leading edge thereof, is selected to enhance rotorblade performance, for example to increase the hover and liftcapabilities of the rotary-wing aircraft. Rotor blades are subjected tohigh stresses and strains resulting from aerodynamic forces developedduring operation.

BRIEF DESCRIPTION OF THE INVENTION

According to one embodiment of the invention, a bond fixture includes afirst frame defining a chamber configured to receive a leading edge of arotor blade and a second frame pivotally coupled to the first frame. Thesecond frame is movable between a first position and a second position.In the second position, the second frame restricts movement of the bondfixture relative to the rotor blade. At least one supporting assemblyextends from the first frame towards the chamber. The at least onesupporting assembly is adjustable to apply a pressure to an adjacentsurface of the rotor blade.

In addition to one or more of the features described above, or as analternative, in further embodiments the first frame includes a first armand a second arm coupled by a connecting member.

In addition to one or more of the features described above, or as analternative, in further embodiments the second frame is pivotallycoupled to a distal end of the second arm.

In addition to one or more of the features described above, or as analternative, in further embodiments a length of the second arm issubstantially greater than a length of the first arm.

In addition to one or more of the features described above, or as analternative, in further embodiments the at least one supporting assemblyincludes a supporting assembly coupled to the connecting member of thefirst frame.

In addition to one or more of the features described above, or as analternative, in further embodiments the supporting assembly coupled tothe connecting member includes a pad having a contoured surfacecomplementary to the leading edge of the rotor blade.

In addition to one or more of the features described above, or as analternative, in further embodiments the at least one supporting assemblyincludes a pair of supporting assemblies coupled to the first arm andthe second arm and extending towards the chamber.

In addition to one or more of the features described above, or as analternative, in further embodiments the pair of supporting assembliesare substantially aligned.

In addition to one or more of the features described above, or as analternative, in further embodiments each of the pair of supportingassemblies includes a pad having a contoured surface complementary to anadjacent surface of the rotor blade.

In addition to one or more of the features described above, or as analternative, in further embodiments wherein a locking mechanism isconfigured to couple to the first frame and the second frame to lock thesecond frame in the second position.

In addition to one or more of the features described above, or as analternative, in further embodiments in the second position, the secondframe is configured to contact a blade cuff of the rotor blade.

In addition to one or more of the features described above, or as analternative, in further embodiments at least one another supportingassembly extends from the second frame towards the chamber, the at leastone another supporting assembly including a pad configured to abut asurface of the blade cuff.

According to another embodiment, a method of bonding a de-ice fairing toa rotor blade includes installing the de-ice fairing to the rotor bladeand positioning a bond fixture about the rotor blade. The bond fixtureincludes a first frame and a second frame. The second frame is rotatedfrom a first position to a second position relative to the first frame.At least one supporting assembly of the bond fixture is adjusted toapply a pressure to an adjacent surface of the rotor blade and de-icefairing. Localized and constant pressure is applied to the de-icefairing.

In addition to one or more of the features described above, or as analternative, in further embodiments positioning the bond fixture aboutthe rotor blade includes disposing the leading edge of the rotor bladewithin a chamber defined by the first frame.

In addition to one or more of the features described above, or as analternative, in further embodiments rotating the second frame from afirst position to a second position includes installing a lockingmechanism coupled to the first frame and the second frame to selectivelylock the second frame in the second position.

In addition to one or more of the features described above, or as analternative, in further embodiments the at least one support assemblyincludes a pad, and the pressure applied by the pad to the rotor bladeis adjusted by changing the position of the pad relative to the rotorblade.

In addition to one or more of the features described above, or as analternative, in further embodiments applying localized and constantpressure to the de-ice fairing includes retaining the bond fixture aboutthe rotor blade for an extended period of time.

In addition to one or more of the features described above, or as analternative, in further embodiments comprising applying heat to thede-ice fairing during the application of localized and constantpressure.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the invention, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of an example of a rotary wing aircraft;

FIG. 2 is a perspective view of an example of a rotor blade of a rotarywing aircraft;

FIG. 3 is a perspective view of a bond assembly for bonding a de-icefairing to a root end of a rotor blade according to an embodiment;

FIG. 4 is another perspective view of a bond assembly for bonding ade-ice fairing to a root end of a rotor blade according to anembodiment;

FIG. 5 is a side view of a bond assembly for bonding a de-ice fairing toa root end of a rotor blade according to an embodiment;

FIG. 6 is a side view of a first frame of a bond assembly for bonding ade-ice fairing to a root end of a rotor blade according to anembodiment;

FIG. 7 is a perspective view of a second frame of a bond assembly forbonding a de-ice fairing to a root end of a rotor blade according to anembodiment;

FIG. 8 is a perspective view of a portion of a bond assembly mountedabout a rotor blade according to an embodiment;

FIG. 9 is a perspective view of the bond assembly mounted about a rotorblade according to an embodiment; and

FIG. 10 is a method of bonding a de-ice fairing to the root end of therotor blade according to an embodiment.

The detailed description explains embodiments of the invention, togetherwith advantages and features, by way of example with reference to thedrawings.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 schematically illustrates a rotary-wing aircraft 10 having a mainrotor system 12. The aircraft 10 includes an airframe 14 having anextending tail 16 which mounts a tail rotor system 18, such as ananti-torque system for example. The main rotor assembly 12 is drivenabout an axis of rotation A through a main gearbox (illustratedschematically at T) by one or more engines E. The main rotor system 12includes a plurality of rotor blade assemblies 20 mounted to a rotor hubassembly H. Although a particular helicopter configuration isillustrated and described in the disclosed non-limiting embodiment,other configurations and/or machines, such as high speed compoundrotary-wing aircraft with supplemental translational thrust systems,dual contra-rotating, coaxial rotor system aircraft, turbo-props,tilt-rotors, and tilt-wing aircraft are also within the scope of theinvention.

Referring to FIG. 2, each rotor blade assembly 20 of the rotor assembly12 generally includes a root section 22, an intermediate section 24, atip section 26, and a tip cap 28. Each rotor blade section 22, 24, 26,28 may define particular airfoil geometries to tailor the rotor bladeaerodynamics to the velocity increase along the rotor blade span. As,illustrated, the rotor blade tip section 26 may include an anhedral form(not shown); however, any angled or non-angled forms such as cathedral,gull, bent, and other non-straight forms are within the scope of thepresent invention. The anhedral form (not shown) as defined herein mayinclude a rotor blade tip section 26 which extends at least partiallyout of a plane defined by the intermediate section 24.

The rotor blade sections 22-28 define a span R of the main rotor bladeassembly 20 between the axis of rotation A and a distal end 30 of thetip cap 28 such that any radial station may be expressed as a percentagein terms of a blade radius x/R. The rotor blade assembly 20 defines alongitudinal feathering axis P between a leading edge 32 and a trailingedge 34. A de-ice fairing 36 is generally bonded to the root end 22 ofthe rotor blade 20, adjacent the blade cuff 38.

A bond assembly 40 for bonding the de-ice fairing 36 to the rotor blade20 is illustrated in FIGS. 4-9. The bond assembly 40 includes a firstframe 42 configured to mount about the leading edge 32 of the rotorblade 20 and a second frame 44 configured to couple to an opposingsurface 46 of the blade cuff 38. The first frame 42 is best shown inFIG. 6 and includes a first arm 50 and a second arm 52 coupled by aconnecting member 54. In the illustrated, non-limiting embodiment, thefirst and second arms 50, 52 are arranged parallel to and opposite oneanother in a generally aligned manner such that the first and secondarms 50, 52 are separated by a distance. The second arm 52 issubstantially longer than the first arm 50. For example, the second arm52 may be sized such that when the bond assembly 40 is attached to arotor blade 20, the free end 56 of the second arm 52 is arranged nearthe surface 46 of the blade cuff 38. In an embodiment, one or moreL-shaped brackets 57 may extend from a central portion of the second arm52. When the first frame 42 is mounted to the rotor blade 20, theL-shaped bracket 57 is configured to abut and maintain contact with aportion of the rotor blade 20, such as the blade cuff 38 for example.

The first frame 42 generally defines a chamber 58 within which the rotorblade 20 is positionable. During installation of the bond assembly 40about a rotor blade 20, the leading edge 32 is disposed generallyadjacent the connecting member 54 of the first frame 42. In anembodiment, a first support assembly 60 extends perpendicularly from theconnecting member 54 into the chamber 58, such as at an orientationsubstantially parallel to the first arm 50 and the second arm 52thereof. The first support assembly 60 may be coupled to or integrallyformed with the connecting member 54. Arranged at the distal end of thefirst support assembly 60 is at least one pad 62 formed from anysuitable material, such as rubber or another resilient plastic forexample. In the illustrated, non-limiting embodiment, an inlet 64 formedin a surface of the pad 62 has a contour generally complementary to theleading edge 32 of the rotor blade 20. As a result, when the bondassembly 40 is mounted about the rotor blade, the leading edge 32 isdisposed within the inlet 64. However, it should be understood that inother embodiments, the inlet 64 may be formed in the connecting memberof the first frame.

A pair of second support assemblies 66 extends perpendicularly from thefirst arm 50 and the second arm 52, respectively, into the chamber 58.The pair of second support assemblies 66 may be located substantiallycoaxially, as shown in FIG. 5. Each of the second support assemblies 66may additionally include one or more pads 68 configured to contact anadjacent surface of the rotor blade 20. The exposed surfaces of the pads68 are generally complementary to the adjacent surface of the rotorblade 20. The second support assemblies 66 cooperate to apply a force toopposing surfaces of the rotor blade 20.

In an embodiment, one or more of the first support assembly 60 and thesecond support assemblies 66 are movably mounted to the first frame 42.In the illustrated, non-limiting embodiment, a nut 70 is mounted to thefirst frame 42 adjacent each of the first support assembly 60 and thesecond support assemblies 66. The assemblies 60, 66 include threadedfasteners 72 engaged with these nuts 70, such that rotation of thethreaded fastener 72 may be used to control movement of each of theassemblies 60, 66 individually, relative to the first frame 42. Theadjustment of the position of the assemblies 60, 66, and therefore ofthe first pad 62 and the second pads 68 may be used to control thepressure applied by the plurality of pads 62, 68 to the various surfacesof the rotor blade 20. It should be understood that the threadedfastener 72 and nut 70 described herein to adjust the position of thepads 62, 68 is intended as an example only, and other suitablemechanisms are contemplated herein.

With reference now to FIG. 7, the second frame 44 includes a support 74and a connector 76. In the illustrated, non-limiting embodiment, theconnector 76 extends at an angle to the support 74. The connector 76 isconfigured to attach the second frame 44 to the distal end 56 of thesecond arm 52 of the first frame 42. In an embodiment, the connector 76includes a clevis portion having two generally parallel arms 78 thatdefine an opening 80 within which the free end 56 of the second arm 52is received. However, other constructions of the connector 76 are alsocontemplated herein.

A pin or other fastener 82 may be used to couple the first and secondframes 42, 44 such that the second frame 44 is rotatable relative to thefirst frame 42 about an axis defined by the pin or fastener 82. Throughthis rotation, the second frame 44 is movable between a first position,best shown in FIG. 8, and a second position, best shown in FIG. 9. Asecond pin or fastener 84 may be used to selectively lock the secondframe in one of the first position and the second position. In anembodiment, when the second frame 44 is in the second position, thesupport 74 is oriented substantially parallel to the connecting member54 of the first frame 42.

Mounted to the support 74 of the second frame 44 is a third supportassembly 86. In an embodiment, the third support assembly 86 isconfigured to extend generally perpendicular to the support 74 such thatwhen the second frame 44 is in the second position, the third supportextends 86 towards the chamber 58 and is substantially parallel to thefirst arm 50 and the second arm 52 of the first frame 42. The thirdsupport assembly 86 may be coupled to or may be integrally formed withthe support 74. At least one pad 88 is positioned at the distal end ofthe third support assembly 86.

When the second frame 44 is in the second position, the at least one pad88 is configured to contact a surface 46 of the blade cuff 38 closest tothe trailing edge 34 of the rotor blade 20. The third support assembly86 may be fixedly attached or may be movably mounted to the support 74of the second frame 44. In the illustrated, non-limiting embodiment, athreaded fastener 90 and nut 92 may cooperate to control the position,and therefore the pressure, applied by the third support assembly 86 tothe blade cuff 38.

With reference now to FIG. 10, a method of bonding a de-ice fairing tothe root end of the rotor blade 20 includes installing the de-icefairing via a dry fit about the leading edge of the rotor blade 20, asshown in block 102. In an embodiment, installation of the de-ice fairingincludes masking the outer surfaces of the de-ice fairing in a knownmanner. In block 104, the bond fixture 40 is positioned about the de-icefairing. Positioning of the bond fixture 40 includes locating theleading edge of the rotor blade 20 within the chamber 58 defined by thefirst frame 42. In addition, when the bond fixture 40 is positionedabout the de-ice fairing, the second frame 44 is in the first position,such that the second frame 44 is rotated vertically to provide aclearance to insert the rotor blade into the bond fixture 40. The secondframe 44 is then pivoted and locked in the second position, as shown inblock 106, such that the support 74 of the second frame 44 is generallyparallel to the adjacent surface 46 of the blade cuff 38.

In block 108, the plurality of pads 62, 68 associated with the firstframe 42 may be movably adjusted to apply a desired pressure to the bondline of the de-ice fairing and the rotor blade 20. In an embodiment, thepads 62, 68 are adjusted by rotating the corresponding fasteners 72 ofthe first and second support assemblies 60, 66 via hand or another tool.When in the second position, the engagement between the second frame 44and the blade cuff 38 is intended to restrict movement of the bondfixture 40 relative to the rotor blade 20, for example due to thepressure applied by the pads 60, 68 to the leading edge of the rotorblade 20. Once the pads 62, 68 are adjusted to apply a desired pressure,the bond fixture 40 is left in place attached to the rotor blade 20 foran extended length of time, such as 24 hours for example, as shown inblock 110. The de-ice fairing may be maintained at room temperature, oralternatively, may be heated during the application of pressure by thebond fixture 40. For example, in an embodiment, heating elements may beassociated with the pressure pads to accelerate the adhesive cure cycle.

The bond assembly 40 illustrated and described herein provides localizedpressure to a desired area of the rotor blade, specifically to the rootend where the de-ice fairing is located. The small size of the bondassembly 40 allows the bonding process to be performed in a fixedlocation and during both the manufacture of a new rotor blade 20 and therepair of an existing rotor blade 20.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

What is claimed is:
 1. A bond fixture comprising: a first frameincluding a connecting member, a first arm, and a second arm, the firstarm and the second arm are oriented generally parallel to one anotherand extend from opposing ends of the connecting member, an axial lengthof the second arm is greater than an axial length of the first arm and adistal end of the second arm is arranged at an angle to the first arm,wherein a chamber configured to receive a leading edge of a rotor bladeis defined between the first arm, a portion of the second armoverlapping the first arm, and the connecting member; a second frameincluding a support movably coupled to the distal end of the second arm,the second frame being movable between a first position and a secondposition, wherein in the second position, the support is arrangedexternal to said chamber and is oriented generally parallel to theconnecting member; and at least one supporting assembly extending fromthe first frame towards the chamber, the at least one supportingassembly being movable relative to the first frame to apply a pressureto an adjacent surface of the rotor blade, wherein the at least onesupporting assembly includes a supporting assembly extending from theconnecting member into the chamber.
 2. The bond fixture according toclaim 1, wherein the second frame is pivotally coupled to the distal endof the second arm.
 3. The bond fixture according to claim 2, wherein alength of the second arm is substantially greater than a length of thefirst arm.
 4. The bond fixture according to claim 1, wherein the atleast one supporting assembly includes a supporting assembly coupled tothe connecting member of the first frame.
 5. The bond fixture accordingto claim 4, wherein the supporting assembly coupled to the connectingmember includes a pad having a contoured surface complementary to theleading edge of the rotor blade.
 6. The bond fixture according to claim1, wherein the at least one supporting assembly includes a pair ofsupporting assemblies coupled to the first arm and the second arm andextending towards the chamber.
 7. The bond fixture according to claim 6,wherein the pair of supporting assemblies are substantially aligned. 8.The bond fixture according to claim 6, wherein each of the pair ofsupporting assemblies includes a pad having a contoured surfacecomplementary to an adjacent surface of the rotor blade.
 9. The bondfixture according to claim 1, wherein a locking mechanism is configuredto couple to the first frame and the second frame to lock the secondframe in the second position.
 10. The bond fixture according to claim 1,wherein in the second position, the second frame is configured tocontact a blade cuff of the rotor blade.
 11. The bond fixture accordingto claim 10, wherein at least one another supporting assembly extendsfrom the second frame towards the chamber, the at least one anothersupporting assembly including a pad configured to about a surface of theblade cuff.
 12. The bond fixture according to claim 1, furthercomprising a heating element associated with at least one of the firstframe and the second frame.
 13. A bond fixture comprising: a first frameincluding a connecting member, a first arm, and a second arm, the firstarm and the second arm are oriented generally parallel to one anotherand extend from opposing ends of the connecting member, an axial lengthof the second arm is greater than an axial length of the first arm and adistal end of the second arm is arranged at an angle to the first arm,wherein a chamber configured to receive a leading edge of a rotor bladeis defined between the first arm, a portion of the second armoverlapping the first arm, and the connecting member; a second frameincluding a support coupled to the first frame, the second frame beingmovable relative to the first frame, wherein the second frame is movableto a position such that the support is arranged external to said chamberand is oriented generally parallel to the connecting member; and atleast one supporting assembly extending from the first frame, whereinthe at least one support assembly includes a supporting assemblyextending from the connecting member into the chamber, the at least onesupporting assembly being movable relative to the first frame to apply apressure to the rotor blade, wherein the bond fixture is operable tobond a de-ice fairing to a rotor blade via: installing the de-icefairing to the rotor blade; positioning the bond fixture about the rotorblade; rotating the second frame relative to the first frame; adjustingthe at least one supporting assembly to apply pressure to a surface ofthe rotor blade and de-ice fairing; and applying localized and constantpressure to the de-ice fairing.